Lens-grinding tool.



Vv" P. HLL.

LENS GRINDIN TOUL.

APPLlcAioN FILED luLY 20, 19m.

2 SHEETS-SHEET Z.

Paen'ted Nov, 30, 1915.

Figs. 3 and 5, are filled with pitch orV other grinding material of the same general` character asthe grinding segments. This maintains asmooth grinding surface between the segments and uniform with the segments. -These gaps,`however, do not become very great and need not at the most exceed a quarter ot' an inch in thickness. lVhen the tool is expanded, the gaps are filled and then the wheel is retinished as stated to obtain the original curvatures. Hence, this tool is adapted to be used at all times for grinding a uniformv surface upon all the lenses. A The invention claimed is y l. A lens grinding tool including a rotatable hub portion, a series of segmental plates radiallyexpansible on said hub portion, abrasive retentive material secured upon said segmental plates and means for simultaneously expanding said segments.

2. Aflens grinding tool including a rotatable hub portion, segments made of suitable` grinding material mounted expansively upon said hub portion, centrally located means for Vsimultaneously expanding said segments and grinding material filling the gaps-4 between said segments whenexpanded.

3. A lens grinding tool including a rotatable hub portion, a series of plates radially expansible on said hub portion, a segment of grinding material secured upon each segmental plate, and suitable grinding4 material filling the gaps between the segmental plates and segments ot grinding material when expanded. 4. A lens grinding tool including a rotatable hub, a series of segmental plates mounted on said hub so as to be radially exl panded, segments of grinding material secured on said segmental plates, annular plates beside said segments immovable with relation to the hub and radially slotted, and clamping bolts extending through said segments and the slots in said side plates.

' g5. A lens grinding tool including a rotatable hub, a series of segmental plates mounted on said h ub so as tobe radially expanded, segments of grinding material s ecured on said segmental plates,'annular plates beside said segments immovable with relation to the hub 'and radially slotted, clamping bolts extending through said segments and the slots in said side plates, and

segmental a single means for radially expanding all of said segmental plates.

6. A lens grinding tool including a rotatable hub, an annular rim rigid with and surrounding and spaced from said hub, seg- A mental plates on the peripherv of said rim,

,arms secured to said plates and extending radially inward through holes in sald rmi,

a sleeve adapted to screw on said hub and having an inner beveled surface adapted to engage the arms of all of the segmental plates and -sin'iultaneously expand said plates, and grinding material secured upon said segmental plates.

7. A lens grinding tool including a rotatable hub', an annular rim rigid with said 75 hub and surrounding and spaced from the same, segmental plates on the outer surface of said rim, arms extending from said segmental plates radially inward through holes in the rim, means for simultaneously acting on said arms for radially expanding said segmental plates, grinding material secured Y on saidplates, a radial ring rigid with said rim and located at one side of said segmental plates and grinding segments, a radial ring at the other side of' said segmental plates and grinding segments and surrounding said rim, said rings having radial slots, and clamping bolts extending through the grinding segments and the slots of said rings.

8. A lens grinding tool includinfT a rotatable hub, an annular rim rigid withsaid .hub and surrounding and spaced from the same, segmental plates on the outer surface of said rim, arms extending from said segmental plates radially inward through holes in the rim, grinding material secured on said plates, a radial ring rigid with said rim and located at the side oil said segmental plates and grinding segments, a radial ring at the other side of said segmental plates and` grinding segments and suii'rounding said rim, said rings having 'radial slots, clamping bolts extending through the grinding segments and the slots of said rings, and a sleeve adapted to be screwed on said hub with its inner surface beveled to engage corresponding beveled edges of the arms from said segmentgl/ plates for 'adially expanding them and the grinding segments.

In witness whereof, I have hereunto affixed my signature in the presence of the witnesses herein named.

VILLIAM P. HALL.

lVitnesses:

J. H. VVnLLs, R. G. Locixwoon. 

